Fluid mixer-reactor



pm w, E951 J. G. ALLEN FLUID MIXER-REACTOR Original Filed July 6,v191155` QUENCH W F E L w D 8 4 N Y lnn/ F EW; L O IJ DR.

POROUS REFRACTORY HYDROCARBONS HYDROCARBONS AIR FIG-3 lNvENToR J.G.ALLEN BY u s ATTORNEY Patented pr. 10, 1951 UNITED STATES vAFENT OFFICEFLUID MIXER.-REAC'IORv John Gordon Allen, Bartlesville, Okla., assignerto Phillips Petroleum Company, a corporation of Delaware Originalapplication July 6 1943, Seriall No. 493,671. Divided and thisapplication `October 30, 1945, Serial No. 625,916

Claims- 1 This invention relates to the. conversion of hydrocarbons andto the production of dioleiin hydrocarbons. A preferred. modificationrelates to the decomposition of light, normally liquid. hydrocarbonsunder conditions chosen for ope timum production of dioleflns aided bythe action of free oxygen on said hydrocarbons. Specific aspects includean apparatus and method of operating which favor a partial oxidation othydrocarbon reactantsin such manner that a very rapid temperature riseto the desired range` isV attained. This application is a division ofcopending application. Serial No. 493,671,v led July 6, 1943, issuedOctober 30, 1945, as Patent No. 2,387,731.

The production of 10W-boiling diolefinic hydro.- carbons such asbutadiene, isoprene, piperylene, etc., has recently become of vitalimportance for` the manufacture of synthetic rubber-like ma.- terials.In perhaps the most important type of synthetic rubber the dioleiinicconstituent comprises about 75 per cent of the raw material..

While relatively highyields ofdiolens may bel obtained through carefullycontrolled selective.

catalytic processes, for example",4 the catalytic dehydrogenationof.normalbutenes to butadiene, such processes suffer somewhat. from the.disad vantage of requiringr a careful isolation of. feed. stocks whichmay be needed for other purposes.y

Furthermora a; high initial capital. expenditure is` required.

In order to obtain asubstantial production of' diolens in airelativelyshort period of time-and, to utilize lcssva-luablc .stocks in so. doing.atten:v

temperature range is attained very rapidly, and

unless the reaction products are in turny rapidly cooled, thehydrocarbons will undergo extensive reactions other than those. desired,with conse@ quent reduction in yield'. I have found that an effectiveway tol attain the desired temperature level almost instantaneously isto admix. an oxy.v

ecn-containing. sas.. with c r. without incr-t diluents, with apartially preheated charge stock in a particular manner chosento promotea par-1 tial oxidation ofthe hydrocarbons, as more fully hereinafterdisclosed and. discussed.

An object of this; invention is to. provide apev paratus useful ineffecting chemical reactions.

Another object of this invention is to provfjdcr such apparatus;particularly adapted for high temperatureoperation.

A further object is to' effect a rapid and inti-e,

mate: intermixture` of two gases.

Yet another object isy to provide apparatus 4 suited to the catalytic'oxidation of organic: ma-` terials.

Furtherl objects and advantages of the invention will become apparent tooneA skilled in the art from the accompanying disclosure andA dis.cussion;

In order to provide a better understanding of: the invention and toillustrate the preferred features thereof the accompanying drawingisproa. vided which shows in somewhat diagrammatic form one arrangementof apparatus.. and; whichl also showsl in some: detail preferred.structures which are particular features of: the present ina.

vention. Figure l` isv a simple flowdiagram inwhich one-form of reactoris shown in detail, as.` used for the production of diolensy whileVEig.Y ures 2 and 3v illustrate'. other preferred forms of the reactor.

As particularly adapted for the oxidation of. hydrocarbons, the reactorof thepresent inverniv tion is provided with. a porous. refractory body:

coated with an oxidation catalyst. This? body is positionedV withrespect,v to theV rest of' the ap paratus so that hydrocarbon: feedintroduced 'ad-1 jacenty thereto passes; immediately away from theIporous body. Means. are. provided: for passingranoxidizing gas throughthe catalystfcoated porous" refractory into` admixture with thehydrocarbons.

The body itself is shaped and positioned in, a novel manner ensuring.intimate mixture of the: oxidizing gas with the hydrocarbons. In orderto bring out the various; featuresof theapparatus there. will bedescribed now, thelutilization there-v of in producingloW-boilingdiolens byoxidation. It will bc appreciated that numerous other chemicalreactions' may likewisebe. effected in;`

the apparatusl of this invention with orv Without; various modificationswhich will beobvious tof one skilled inthe art, in View of; the speciiicdis;

closure of Various preferred structures. givenherein.

In the preferred manner of carrying out thez production of 10W-bcling`diolens in` accordance:

with the principles of this invention, a nonaromatic hydrocarbondistillate such as cracked or straight-run naphtha is diluted with steamor other non-oxidizable diluent, is brought to a temperature of about1100 F. or slightly higher, and then passed rapidly past theincandescent surface of a porous refractory material through which airin carefully controlled proportions is being introduced. The resultinggaseous admixture is maintained at the desired reaction temperature forthe short time required and quenched immediately thereafter to stop thereaction. The porous refractory material referred to preferably iscoated with a catalyst, such as a metal oxide, which catalyzes theoxidation of hydrocarbons. The introduction of oxygen through saidrefractory member in the manner described provides a very rapid andintimate interrnixture of hydrocarbon charge with oxygen and the desiredoxidation is at least partially effected at the refractory surface. Theresult is the maintenance of a highly heated surface past which thehydrocarbon stream flows. It will be seen that the temperature of thehydrocarbon stream is raised almost instantaneously several hundreddegrees from the preheat temperature tothe reaction temperature. Due tothe intimate mixture of oxygen with hydrocarbons thus effected theoxidative reaction continues in the portion of the reaction zoneimmediately following the incandescent refractory and serves to maintainthe temperature of the mixture in the desiredV range in spite of thehighly endothermic cracking reaction which is being affected. In otherwords, the hydrocarbons are rst rapidly raised 'to reaction temperatureand second maintainedv at reaction'temperature by the introduction oflimited amounts of oxygen in the particular manner described. i

It `has been found that the best results are obtained when a diluent,such as steam, nitrogen, an oxide of carbon, etc., is mixed with theselected hydrocarbon charge stock prior to its passage through thepreheat zone. This serves to minimize any reaction in said zone andpermits a relativelyhigher temperature to be maintained therein withoutthe occurrence of an appreciable amount of coking.v The'diluent servesduring thereaction to help control temperatures and partial pressure ofreactants and enables the attainment of a high conversion to diolei'lns.Preferably the mol ratio of "diluent to oil vapor is in the range offrom about 3:1 to about 6:1. While the total pressure of the reactionmixture should generally be above atmospheric, the use of agreat'super-atmospheric pressure will appreciably reduce the yield oflow-boiling diolei'lns. In most cases a preferred operation will involvethe use' of only a suflicient super-atmospheric pressure to overcomelthe pressure drop through the apparatusand provide a few pounds ofsuperatmospheric pressure at the exit of the reaction zone.

H'Any suitable source of oxygen may be utilized, but air is ordinarily'found to be most convenient. The inert constituents of the air have anadvantageous diluting effect in the reaction zone. The amount of freeoxygen utilized must be carefully controlled to obtain a suicientlyrapid and great temperature rise on the one hand, While avoiding' unduedestruction of hydrocarbons on the other hand. With the type of chargingstocks described herein and under the given temperature and timeconditions, it is necessary that free oxygen be used in an amountsubstantially between about 0.15 and 0.25 pound per pound of hydrocarbonmaterial to attain the most satisfactory results. In the case of air,this requires an air-hydrocarbon weight ratio in the range of about 0.7to 1.2.

An important feature of the present invention is the catalyst-coveredporous refractory body, particularly with respect to its composition andto its position relative to the steam-hydrocarbon stream. The bodyproper should have a relatively large surface area, and may comprise anysuitable refractory material which is stable at the high temperaturesencountered. The porosity is such that the required flow of air or otheroxygencontaining gas may be maintained without requiring too high apressure drop across the body, while at the same time providing for avery intimate admixture of oxygen with hydrocarbon. The catalyst coatingmay comprise one or more high-melting oxides of metals of groups IIIB,IVA, VA, VIA, or VIIA of the periodic system as grouped by Mellor,Modern Inorganic Chemistry, Longmans, Green & Co. (1939), page 118. Suchcoating may be applied in any suitableY manner,

exemplary of which is`the impregnation of the body with, or sprayingupon the surface of the` body, a solution of a metal salt, followed bycalcining to convert the salt to the oxide. Preferred combustioncatalysts are ThOz, ZrOz, and W03.

The body thus coated with the combustion catalyst is placed in theapparatus in such way with respect to the ow of hydrocarbon reactantsthat the latter contact the same for only a very short period of time,and then pass away to the re- As stated above,

mainder of the reaction Zone. this provides sufficient combustion toraise the temperature to the desired range, while maintenance oftemperature during the ensuing endothermic cracking is provided bycontinued action of the admixed oxygen with the hydrocar-V bons in thebalance of the reaction Zone. The shape of the porous body will besomewhat dependent on-the design of the reactor and its locationtherein. One preferred shape is that of a ysures a rapid temperatureincrease only to thel desired level whereas if the hydrocarbon wereallowed to remain in close contact with the incandescent Ybody for amore substantial portion of the total reaction time a decompositionentirely too extensive for satisfactory diolen production would beencountered. The reaction time allowed between introduction of preheatedcharge to admixture with air and the subsequent shock cooling ispreferably between about 0.1 and about 0.2 second.` Usually-an emptyreaction chamber is provided, the size of which is correlated with flowrates togive the proper reaction time. However, the reaction zone may bepartially lled with metal or refractory packing to provide a moreextended Surface which seems to favor the continuance of the alreadyinitiated combustion. Immediately upon completion ofv the conversion thetotal reaction mixture is quenched, preferably to about 400 F. or lower.

In the choice of chargingstock for dioleiina` production in .the'instant process, a certain amount of latitude is permissible, whichadds to the value of the process, particularly for use in Aa petroleumren'ery where changing operations affect the availability offanyparticular type of stock. -Asstated before, the ordinarily less'valuable stocks are generally utilizable, thus enhancing the economicstatus `of the process. Thematerial used should, however, generally'-f'all within the following classification: it Should be non-Varomatic, that is, have a content lof aromatic hydrocarbons less thanabout .ten Iper cent, Yand preferably less than live per centi; .itshould be .normally liquid, and preferably higher boiling than thediolefin to be produced; it should be relatively light, that is,substantially .boiling belowabout 600 F.-preferably the material com-.prises vhydrocarbons having at least four and not more than twelvecarbon 'atoms 'per molecule. :As examples of such materials may bementioned straight-run .naphthas of narrow `or wide boiling range,catalytically or .non-catalytically cracked naphthas of narrow or -wideboiling range, or mixtures of such naphthas.

In Figure l, the naphtha or other oil to be cracked is introduced vialine IIJ, joined by recycled material from line l2 if desired, and mixedwith vsteam from line I4 in the proper ratio disclosed hereinabove. Theresulting mixture is passed through coil I6 in Apreheater furnace kI8fr.

where the temperature is rapidly raised to about 1100-1200 F. The thuspreheated `material then flows Via line into reactor 22, rst enteringthe vmixing T 24. Disposed within this T with its axis at a right angleto the 'entering stream is a porous refractory fcone 26 coated with Aacombustion catalyst. The cone inserted about halfway across thebull-head opening of the T so oil Yvapors flow across the cone incontact with the surface where air enters, yet leaving enough clearanceso that there is no great restriction to oil flow. Air is admitted tothebaseof cone 26 via line 28 in a quantity based on the quantity of chargeoil as described herein. The stream of preheated oil and steam flowspast the cone 2E `and immediately is turned to llow 'parallel With theaxis thereof away from the cone on into the next portion of reactor 22.The air owing through cone 26 `into reactor 22 mixes with the oil and aconsiderable proportion of the total combustion voccurs in T 24 onoradjacent 'the `catalyst-coated surface of cone 26, which is Vheated toincandescence. The oxygen and the hot products of combustion rapidlyAmix with the hydrocarbon and immediately raise the temperature of thetotal lstream tothe desired cracking lrange. It will be 'seen that theconstruction of T 24 ensures ease of nstallation'and replacement, whichis of particular advantage when'such high temperatures are encountered.

After-cracking is completed in reactor 22, the total eiiluents leavingvia line 30 are immediately `quenched by cool liquid, such as 'water oroil, entering via line 32. The yquenched material passes into aseparation system indicated diagrammatically by unit E4. Someincompletely converted material may be vrecycled via line l2, but itshould irst -be Aseparated A,from aromatic hydrocarbons by suitablemeans. Low-boiling "material is removed via line Stand high-boilingmaterial vvia -line 49, while a fraction containing desired di'olefins'is passed via line 42 to diolen recovery equipment 44. This may includesolvent extraction, extractive distillation, azeotropic distillation,formation and decomposition of Cil .rium salt to the oxide.

cent based on the charge.

,from the-process effluents.

'melena-metal salt :complexes .such as diciefirl* cupr'ous chloridecomplex, or 'any other suitable means known .to the art. Nonv-diolen'icmaterial is removed through line 46, while the desired diolens, such asbutadiene, are recovered through line 48. It will be understood that theC5 and/0r C6 andl even Vheavier diolens vmay .be similarly recovered.

Figure 2 illustrates another imanner'of fashion'- ing the portion of'reactor 22 containing the iporous refractory. An L 50takesthepla'c'e ofT 24. A porous refractory YVcatalyst-coated .plate 52 iis placed .in the.L `'as shown so that air, 'entering through line .'2-8., is introducedinto the 'flowing'oil stream without too much restriction to the 'oillio'w. The oil-steam mixture passes `adjacent plate 52 and thenimmediately away fro'm .itinto thereactionzoneproper.

Figure 3 .illustrates another preferred structur of this invention,which employs a Venturishaped porous lrefractory :catalyst-'coated tube54 in the oil-steam flow line, :allowing .for air Ainjection .from allsides of the .flowing oil stream. .An annular space 56 raboutVenturi-tube .54 is .provided by cylinder 58, into which air from :liney28 is introduced. The Venturi decreases any '.possibility of the centerportion of the flowing oil stream not receiving contact with the air,and provides an added mixing effect due to the pressure drop across theVenturi. The hot gases pass rapidly `from .glowing tube 54 on "into ltheremaining portion of reactor 22.

The .following example is given asa means of illustrating the results`which are obtainable .in producing diolens when using the apparatus ofthis invention. It will be understood, of course, that the exact dataare not `to be construed as unduly limiting .since the vdifferentfactors may be varied within the .preferred ranges as 'heretofore setout.

'A .straight-run naphtha having a boiling .range of 20G-400 F. isadmixed with 5 mois of `steam per mol of oil and preheated to 1100 F.This preheated material is then passed into a reactor similar to thatshown in Figure 1 in contact `with a porous alundum body coated withthorium oxide by impregnation with a solution of thorium nitrateAfollowed by burning to convert the tho- Air, preheated to 500 F., :isintroducedthrough the porous body at the rate of 1.1 pound per pound ofoil charged. 'Based `on the volume of material charged, a reaction timeof 0.2 second is realized, and the temperature at -the outlet of thereactor is 1600 F. The reactor eilluent is immediately quenched withwater to about 350 F. and passed to separating equipment comprisingconventional absorbers and fractionators. The C4 cutis recovered and thebutadiene, which comprises ll5 to 50 per cent of the cut, is separatedtherefrom by extractive distillation with furfural. The weight ratio ofbutadiene to dry gas (C3 and lighter) is 0.11,`and

the over-all yield of butadiene is 4.5 weight 'per Substantial, thoughlesser, amounts of C5 diolens are also recovered While partial oxidationof hydrocarbons for the production of low-boiling diolens has beenvemphasized in the `foregoing discussion, this is lmerely exemplary, forobviously various other .processes Yknown to the art for theoxidation'of vorganic materials may likewise be effected in the novelapparatus described herein. Merely by way of illustration may bementioned the production of methanol, formaldehyde, and otherexif-compounds by the controlled oxidation of methane or natural gas;the production of olefin oxides as by the oxidation of ethylene; thepartial oxidation of highly unsaturated oils to produce drying oils orthe like useful in the manufacture of protective coatings. The apparatusherein disclosed is likewise very advantageous in the production ofphthalic anhydride by oxidation of naphthalene or ortho xylene.

Oxygen-containing fluids which may be used include those containing freeoxygen, such as air, or ozone, or those containing oxygen combined withother elements, e. g. nitrous oxide or nitrogen dioxide. Other fluids,such as chlorine, may be employed to effect oxidation reactions.

The apparatus of the present invention is not necessarily limited inuses to those involving oxidation, for obviously other organic orinorganic chemical reactions such as chlorination, nitration,sulfonation, neutralization of acids with bases, and the like, may beaffected. Such reactions may be carried out either with or withoutcatalysts as desired, and though either gas or liquid or both may beutilized, the advantageous features of the invention are most completelyrealized when both reactants are in the gas phase.

The invention may also be applied to the problems involving physicaladmixture of two fluids even in the absence of chemical reaction. Theporous Venturi illustrated in Figure 3 is particularly to be noted inthis connection as it provides complete and very rapid mixing action.This and the other forms permit streamline flow before and/or after theporous section, with turbulent flow at the point of mixing.

While preferred aspects of this invention have been described, the scopeis not to be limited other than as defined in the appended claims.

I claim:

1. Apparatus suitable for effecting reaction between fluids whichcomprises a cylindrical conduit an elongated portion of which comprisesa reaction chamber, a porous refractory body of relatively large surfacearea within said conduit immediately upstream of said reaction chamberportion and having a catalytic coating on the surface thereof which isin communication with said conduit, means forming with the oppositesurface of said porous refractory body a closed chamber, means forintroducing a first fluid into said closed chamber and thence throughthe pores of said porous refractory body into said conduit, means forflowing a second fluid longitudinally through said conduit past saidporous refractory body, said porous refractory body being so positionedwithin said conduit with respect to said reaction chamber portionthereof that said first fluid flowing through its pores has at leastlateral vector components with respect to said reaction chamber portionof the conduit, whereby rapid and intimate admixture of said rst andsecond fluids occurs at and near said catalyst coated surface and theadmixture immediately flows away from said surface into andlongitudinally through said elongated reaction chamber, and means forwithdrawing iiuids from the downstream end of said reaction chamber.

2. Apparatus suitable for effecting reaction between fluids whichcomprises a tubular T co-mposed of a cylindrical main or through portionand a cylindrical branch portion perpendicular thereto and incommunication therewith, one

part of said through portion beyond the junction with said branchcomprising a reaction chamber more elongated than the other part of saidthrough portion on the opposite side of said junction, a porousrefractory cone axially positioned in and closing said other part havingits apex extending into the central junction portion of said T so as toproduce only a partial restriction of flow therethrough, said porousrefractory cone having a catalytic coating on the outer surface thereofwhich is in communication with said T, means for introducing a firstfluid into said T through the pores of said cone, means for inftroducing a second uid into said T through said branch portion, andmeans for withdrawing fluids from the end of said reaction chamber.

3. Apparatus suitable for effecting reaction between iiuids whichcomprises an elongated tube, a porous refractory section of said tubehaving a restricted cross-section and having a catalytic coating on theinner surface thereof, a casing surrounding said porous section ofrestricted crosssection and forming therewith a closed chamber, meansfor introducing a rst fluid into said closed chamber and thence throughthe pores of said refractory material into the interior of said tube.means for flowing a second fluid longitudinally through said tube, andmeans for withdrawing fluids from said tube at a point downstream fromsaid restricted section.

4. Apparatus suitable for effecting reaction between fluids whichcomprises an elongated tube, a porous section of said tube having arestricted cross-section and having a catalytic coating on the innersurface thereof, a casing surrounding said porous section of restrictedcross-section and forming therewith a closed chamber, means forintroducing a first uid into said closed chamber and thence through thepores of said restricted section into the interior of said tube, meansfor flowing a second fluid longitudinally through said tube, and meansfor withdrawing fluids from said tube at a point downstream from said rstricted section.

5. Apparatus suitable for effecting reaction between fluids whichcomprises an L-shaped conduit, a porous refractory plate disposed in thecorner thereof so as to produce only a partial restriction of flowtherethrough and so as to form a closed chamber between said plate andthe outer corner of said L, said porous refractory plate having acatalytic coating on the surface thereof which is in communication withsaid conduit, means for introducing a first fluid into said closedchamber and thence through the pores of said porous plate into saidconduit, means for owing a second iiuid through said L-shaped conduit,and means for withdrawing fluidsv from said conduit at a pointdownstream from saidiL.

JOHN GORDON ALLEN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,270,989 Taliani July 2, 19181,309,623 Henwood July 15, 1919 1,960,608 Weber May 29, 1934 2,071,119Harger Feb. 16, 1937 2,387,731 Allen Oct. 30, 1945

1. APPARATUS SUITABLE FOR EFFECTING REACTION BETWEEN FLUIDS WHICHCOMPRISES A CYLINDRICAL CONDUIT AN ELONGATED PORTION OF WHICH COMPRISESA REACTION CHAMBER, A POROUS REFRACTORY BODY OF RELATIVELY LARGE SURFACEAREA WITHIN SAID CONDUIT IMMEDIATELY UPSTREAM OF SAID REACTION CHAMBERPORTION AND HAVING A CATALYTIC COATING ON THE SURFACE THEREOF WHICH ISIN COMMUNICATION WITH SAID CONDUIT, MEAND FORMING WITH THE OPPOSITESURFACE OF SAID POROUS REFRACTORY BODY A CLOSED CHAMBER, MEANS FORINTRODUCING A FIRST FLUID INTO SAID CLOSED CHAMBER AND THENCE THROUGHTHE PORES OF SAID POROUS REFRACTORY BODY INTO SAID CONDUIT, MEAND FORFLOWING A SECOND FLUID LONGITUDINALLY THROUGH SAID CONDIUT PAST SAIDPOROUS REFRACTORY